Pin-tumbler lock



Dec. 17, 1929. w, 13, HAINLINE 1339,964

P13 TUMBLER LocK Filed Dec. 13, 1928 I N VEN TOR.

I 5 ATTORNEYS.

Patented ee. 17, 1929 arr sr PIN-TUMBLER LOCK Application filed December 13, 1928. Serial No. 325,760.

The invention relates to improvements in looks of the type having a plurality of springpressed locking pins or tumblers which are slidable in a stationary lock cylinder and projectible into pin bores in a rotatable plug mounted in a bore of said cylinder, the plug being formed with a longitudinal key-way and being equipped with the releasing pins for thetumblers actuated by insertion of a key into said key-way. Locks of this type are often quite easily picked by operation of a suitable instrument upon the releasing pins while exerting a slight turning pressure upon the plug, and it is one aim of the present invention to provide the plug with a safety plate which prevents turning oftheplugsufliciently to operate the look, even though the locking pins may be picked from their initial pluglocking positions.

There are other ways of releasing locks of the type above mentioned, for instance, by drilling away the front portion of the plug sufficiently to permit introduction of a thin metal strip between plug and cylinder for holding the locking pins released after they have been picked to released position; by drilli'n the plug or cylinder and portions of the loc ing pins; and by applying a wrench or the liketo the outer end of the cylinder, goforcibly turning the latter and thereby shearin its safety locking means, and finally re- I moving the cylinderjand plug bodily. It is a further object of the invention to make adequate provision whereby the lock cannot be released-by any of these methods. q

With the foregoing in view, the'invention resides in the novel subject matter hereinafter described and claimed, description being accomplished by reference to the accompanying drawing.

Fig. 1 is a top plan view partly in horizontal section.

Fig. 2 is an outer end or front elevation.

Fig. 3 is a longitudinal sectional view on line 3 -3 of Fig. 2.

Fig. 4 is a vertical transverse sectional view on line 4-4: of Fig. 3.

Fig. 5 is a view similar to Fig. 4 but illustrating the only partially released position to 50 which the locking pins may be picked.

disclosed and while these details will be herein specifically explained, it is to be understood that within the scope of the invention as claimed, variations may be made.

The numeral 6 denotes the stationary lock cylinder for passage through a door 7, the inner end of said cylinder being threaded as at 8 for engagement with a housing 9 of a lock structure of conventional form and constituting no part of .the present invention. .The cylinder 6 is formed with a longitudinal plug bore 10 and with a plurality of transverse pin bores 11. Rotatable in the bore 10 is a plug 12 having the usual lock throw-bar 13 at its inner end and provided at its outer or front end with an outstanding rib or flange 14 disposed at the front end of the cylinder 6. This plug 12 is formed with a longitudinal keyway 15 and with a plurality of pin bores 16 for alinement with the pin bores 11. Springpressed locking pins 17 are slidably received in the pin bores 11 and are projectible into the bores 16 of the plug 12 to lock the latter, and releasing pins 18 are slidable in the bores 16 to be actuated by a key 19 for the purpose of moving the locking pins 17 to released position at which their inner ends are flush with the wall of the bore 10.

All of the details above-described are common in pin tumbler locks and I will now proce'ed to describe my improvements.

A safetyv plate 20 is disposed at the periphery of the plug 12 and is formed with...

openings 21 through which the locking pins -17 normally pass to enter the pin boresf16.

The plug 12 is formed with a longitudinal-recess 22 which receives theplate 20 and is of the same length as the latter, said recess however being of greater width in degrees than said plate. i

If an attempt be'made to pick the'lock in the usual way by successivelyforcing the releasing pins 18 to release the locking pins 17 while exerting a light turning force upon the plug 12, said locking pins 17 may be moved out of the pin bores 16 and when they clear the outer ends of these bores, the thief picking the lock naturally thinks they have cleared the periphery of the plug 12. When tudinal side wall of the recess 22 strikes the plate 20, because of the fact that the inner.

ends of the locking pins 17 still remain'in the openings 21 of said plate (see Fig. 5).

Attention is further invited to the fact that the openings 21 are of larger diameter than the pins 18. Thus these pins 18 cannot establish a rigiddriving connection between the plug 12 and the loosely mounted plate 22, and consequently turning force applied to said plug 12 when attempting to pick the lock, cannot cause said plate to hold the pins 17 released. When using any known way of picking, the pins would be picked to the position of Fig. 5 butthe plug 12 could not rotate suflicientlv to open the look as above explained. If any of the pins should by any possibility be picked to the shear line and supported at picked position by resting upon plate 22, attempt to similarly pick the next pin, would move. said plate 22 and allow the previously picked pin to fall back to locking position, for said plate 22 is inaccessible and could not be held against movement.

Inset in the front end of the cylinder 12 and projecting laterally from the bore-engaging face thereof into the flange 14, is a case liardened metal plate 23 which is disposed in front of the pins 16-17. This plate prevents drilling away or otherwise removing a sufiicient front-portion of the plug 12 to permilt introduction of a thin metal strip between said plug and the cylinder 6 for the purpose of holding the pins 17 released after picking them to released position. Hence, anyone attempting to pick the lock in this manner would also be thwarted.

If anyone should succeed in so injuring the plate 23 as to permit drilling the plug-12 or cylinder 6, or should the plug be so drilled away as to remove said plate, even then cutting of the locking pins 17 by-drilling is prevented, for the reason that the foremost pin 17 is case-hardened. Hence, this pin cannot be cut by drilling and it consequently guards all of the pins behindit.

Swiveled around thefront end of the cylinder 6 is a hard metal ring 24 which so shields said cylinder end as to prevent application of a wrench or the like thereto, so that it cannot be forcibly disengaged from the lock housing 9.

From the foregoing, taken in connection with the accompanyingdrawing, it will be seen that I have made unique provision for insuring against the usual methods employed for the unauthorized openingof locks, and while the details disclosed are preferably followed as above set forth, variations may be made Within the scope ofthe invention as claimed. I

I claim 1. An improvementin a lock of the type embodying a cylinder havingv a-longitudinal plug bore and a transverse pin bore, a plug of the plug, and a key-actuated releasing pin in-said pin bore of said plug; said improvement consisting of a plate at the periphery of .said'plug having an opening through which said. locking pin normally passes, said plug being formed with a peripheral recess receiving said plate and of greater width in degrees than said plate, permitting limited turning of the plug with respect to the plate if the locking pin be picked out of the pin bore of said plug.

3 2. A structure as specified in claim 1; together with a transverse hardened metal plate inset in the lock plug and projecting laterally beyond the bore-engaging face thereof at the front end of the cylinder, said hard metal plate being in front of said pins and preventing sufficient drilling of the plug to permit introduction of a thin pin-holding strip between cylinder and plug; and a hard metal ring swiveled on the front end of said cylinder to prevent application of a wrench thereto. 5

3. A structure as specified in claim 1; together with a transverse hardened metal plate inset in the lock plug and projecting laterally beyond the bore-engaging face thereof at the front end of the cylinder, said hard metal plate being in front of said pin and preventing sufficient drilling ofthe plug to permit introduction of a thin pin-holding strip between cylinder and plug; and a hard metal ring swiveled on the front end ofsaid cyl inder to prevent application of a wrench thereto, said locking pin being hardened to prevent cutting thereof with a drill should said hard metal plate be injured or removed.

In testimony whereof I have hereunto affixed my signature.

\ WALTER D. HAINLINE. 

